Dreamworld staff admitted there had been a "total failure" to identify risks with the ride and a series of equipment failures before the accident should have raised red flags and been investigated.

Police giving evidence said multiple safety recommendations following those incidents were not implemented, including the installation of automatic sensors to detect falling water levels or a simple single total shutdown switch.

The ride was also heavily criticised as "unsafe" as it had no proper maintenance schedules, extensive cracking and corrosion with parts of the structure "propped up with timber".

Workplace Health and Safety engineers said significant alterations to the ride had never been assessed or approved and made the ride "more hazardous"

The tragedy has prompted a review of inspection procedures and a major overhaul of theme park safety across Queensland.

Dr Gary Weiss of Ardent Leisure, which owns Dreamworld, issued a statement to express remorse and deep regret over the accident.

"Our thoughts remain with the victims' families and everyone who has been affected by this terrible tragedy."

Coroner James McDougall is expected to hand down his findings next year.